To convert from any power unit to watts:
\[ \text{Watts} = \text{Power} \times \text{Conversion Factor} \]
\[ 1 \text{ picowatt [pW]} = 10^{-12} \text{ watt [W]} \]
\[ 1 \text{ nanowatt [nW]} = 10^{-9} \text{ watt [W]} \]
\[ 1 \text{ microwatt [µW]} = 10^{-6} \text{ watt [W]} \]
\[ 1 \text{ milliwatt [mW]} = 10^{-3} \text{ watt [W]} \]
\[ 1 \text{ kilowatt [kW]} = 10^{3} \text{ watt [W]} \]
\[ 1 \text{ megawatt [MW]} = 10^{6} \text{ watt [W]} \]
\[ 1 \text{ gigawatt [GW]} = 10^{9} \text{ watt [W]} \]
\[ 1 \text{ terawatt [TW]} = 10^{12} \text{ watt [W]} \]
\[ 1 \text{ petawatt [PW]} = 10^{15} \text{ watt [W]} \]
\[ 1 \text{ Btu/hour [Btu/h]} = 0.293071 \text{ watt [W]} \]
\[ 1 \text{ mechanical horsepower [hp(l)]} = 745.6998715823 \text{ watt [W]} \]
\[ 1 \text{ metric horsepower [hp(M)]} = 735.49875 \text{ watt [W]} \]
\[ 1 \text{ electric horsepower [hp(E)]} = 746 \text{ watt [W]} \]
\[ 1 \text{ air horsepower [ahp]} = 745.69987158 \text{ watt [W]} \]
\[ 1 \text{ boiler horsepower [hp(S)]} = 9812.5 \text{ watt [W]} \]
\[ 1 \text{ kilocalorie/hour [kcal/h]} = 1.162222 \text{ watt [W]} \]
\[ 1 \text{ kilocalorie/minute [kcal/min]} = 69.733333 \text{ watt [W]} \]
\[ 1 \text{ erg/second [erg/s]} = 10^{-7} \text{ watt [W]} \]
\[ 1 \text{ ton of refrigeration [TR]} = 3516.8528420667 \text{ watt [W]} \]